There is no delegate concept in Java The right-side C# program may be mimiced with reflection technology.
在Java中没有delegate的概念,而C#中delegate使用的是类似Java中反射的工具。
import java.lang.reflect.*; import java.io.*; public class Test { public static void main(String[] args) throws Exception { String[] list= {"to","be","or","not","to","be"}; Method m1 = Test.class.getMethod("toConsole",new Class[] {String.class}); Display(m1, list); Method m2 = Test.class.getMethod("toFile",new Class[] {String.class}); Display (m2, list); } public static void toConsole (String str) { System.out.print(str+" "); } public static void toFile (String s) { File f = new File("delegate.txt"); try{ PrintWriter fileOut = new PrintWriter(new FileOutputStream(f)); fileOut.write(s); fileOut.flush(); fileOut.close(); }catch(IOException ioe) {} } public static void display(Method m, String[] list) { for(int k = 0; k < list.length; k++) { try { Object[] args = {new String(list[k])}; m.invoke(null, args); }catch(Exception e) {} } } }
Delegate是引用类型允许间接访问方法。以下是简单和多维的委托Delegate
Delegates are reference types which allow indirect calls to methods. There are single and multicast delegates. ============================================ using System; using System.IO; public class DelegateTest { public delegate void Print (String s); public static void Main() { Print s = new Print (toConsole); Print v = new Print (toFile); Display (s); Display (v); } public static void toConsole (String str) { Console.WriteLine(str); } public static void toFile (String s) { File f = new File("delegate.txt"); StreamWriter fileOut = f.CreateText(); fileOut.WriteLine(s); fileOut.Flush(); fileOut.Close(); } public static void Display(Print pMethod) { pMethod("This should be displayed in the console"); } }
A delegate instance encapsulates one or more methods, each of which is referred to as a callable entity. To add or reduce a list of calls by using operators += or -=. for example Print p = s + v; s += v;
对比可以得出的概念是:Java中没有这个Delegate的概念,但是通过反射的方法可以实现,C#却可以通过直接使用Delegate用来实现函数方法的间接调用。
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时间: 2024-11-08 23:17:19